Tripping device for the bucket door of power shovels



Jan; 15, 1929. 1,699,371

a 4 f/&. 2. ggvvm w gl 2 Q INVENTOR.

//0L am? A. M/ 70/54 L A TTORNEYS.

Patented Jan. I 15, 1929.

UNITED STATES PATENT OFFICE.

HOLGER' L. IIITCHELL, O1 MILWAUKEE, WISCONSIN, ASSIGNOR HARNISCHFEGER CORPORATION, OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

TBIPPING DEVICE FOR THE BUCKET D003 01' POWER SHOVELS.

Application filed November 2, 1925. Serial No. 86,195.

This invention relates to improvementsin tripping devices for the bucket doors of power shovels.

It has been the practice in power shovel operation, heretofore, to trip the bucket door by means ofa rope fixed at one end to the rear end of the roof or covering for the machine and passed through pulleys suspended from :he roof or covering and over a guiding pulley carried by the boom, the other end of the rope being attached to the tripping lever carried by the dipper stick. A suitable weight placed upon the rope between the end thereof fixed to the roof or covering of the machine and one of the pulleys suspended therefrom acts by gravity to take up the slack in the r0 e when the dipper stick is racked in, the welg t thereby acting to automatically keep the tripping rope taut so that a slight jerk upon the latter by the operator will be effective in tripping the latch of the bucket door. In the racking out movement of the dip er stick, the weight is raised accordingly an permits the slack in the tripping rope to be payed out. This tripping device used heretofore has been more or less satisfactory, but is crude in construction and the weight and slack rope swing about in such manner as to interfere with the movement of the operator. In this trippin device, furthermore, the full force or pul necessary to be applied to the dumping end of the trip line must be applied by the operator.

One of the objects of the present invention,

therefore, is to provide an improved trippingv device of the character referred to comprismg means for automatically keeping the trip ing rope taut and which is ositloned beyon the range of movement of t e operator.

Another object is to provide an improved tripping device of the character referred to comprising means associated with the mechanism for racking the dipper stick in and out and operated by this mechanism for automaticall kee in the tripp-in rope taut.

Anothgr obijhcti is to providi an improved trippin device of the character referred to which s all include manually-operable means for applying leverage to the dumping end of the trip line whereby the operator-is relieved of the manual effort necessary in pulling the trip line in devices of this type constructed heretofore.

Other objects and advantages will hereinafter appear.

0 For the pur ose of illustrating the invention, an embo iment thereof is shown in the drawlngs, in which Figure 1 is a side elevation, showing the improved tripping device applied to a power shovel;

Fig. 2 is an enlarged section on line 22 ofFig. 1; and

Fig. 3 is an enlarged section on line 33 of Fig. 1.

- The power shovel shown is of the usual construction, and includes a boom 1, a dipper stick 2 carried thereby and provided at its outer end with the bucket 3 having a dumping door 4 which is held closed and released by a suitable latch 5, the latch being connected by a chain 6 to the tripping lever 7 pivotally connected at 7 to the dipper stick. The mechanism for racking the dipper stick in an out is well known to those skilled in the art, and includes the shipper shaft 8 journaled in brackets 9 secured to the boom, pinions 10 fixed to the shaft and arranged in mesh with racks on the underside of dipper stick 2, and a sprocket wheel 11 also fixed to shaft 8 and driven from the transmission unit of the machine by a sprocket chain (not shown).

The improved tripping device, in the embodiment shown inthe drawings, comprises a flexible element or tripping line 12 connected at 13 to tripping lever 7 and passed over a suitable guiding pulley 14 fixed to one of the brackets 9, line 12 from thence passing around a sheave 15 and secured to a drum 16 fixed upon one end of shipper shaft 8, the pitch diameter of drum 16 eing equal to the pitch diameter of pinions 10. Sheave 15 is rotatabl supported in a suitable frame 17 fixed to a s aft 18 ournaled in bearing members 19 and 20 which may be supported by the longitudinal members21 and 22 whic carry the roof 23 of the cab. A manual] -operable lever 24 is also fixed to shaft 18 an arranged in proximity to the operators position on the machine.

The operation of the improved trip-ping device is as follows: Upon rotation of shipper shaft 8 in a counter-clockwise direction, as viewed in Fig. 1, to cause racking in of the dipper stick 2, drum 16 will rotate in the same direction and wind up the trip line 12 at such a rate that the latter is kept taut, sheave 15 rotating freely at this time in its frame 17. Upon rotation of shipper shaft 8 in a clockwlse direction to cause racking out of the dipper stick, the reverse action takes place, that is, drum 16 rotates to unwind or pay out line 12 at the same rate at which the dipper stick is moved outwardly whereby the line is automatically kept taut, but'prevented from becoming tight enough to trip latch 5. When the operator desires to trip latch 5, he pulls lever 24 toward himself to cause backward pivotal movement of sheave 15 about shaft 18 as a center, line 12 thereby being pulled in and tightened to pull the tripping lever 7 backward to release the latch. It it to be noted that thedistance between the axis of rotation of sheave 15 and shaft 18 is less than the distance between the latter and handle I all'times, which relieves the operator by applying leverage to the dumping end of the trip line, and which has advantages over devices of this type constructed heretofore as regards efliciency, compactness and manner of operation.

For the purpose of illustrating the invention one embodiment thereof has been shown and described, but of course various changes in the size, shape and arrangement of the parts may be made without departing from the spirit of the invention or the scope of the claims.

The invention claimed is:

1. A tripping device for the latch of a dumping door of a power shovel having the usual equipment including a revolving plat--' form and a shipper shaft and comprising manually operable means supported on the revolving platform within reach of the operator, a drum connectible with the shipper shaft and a single flexible element directly engaged with and directly controlled by said manually operable means on said revolving platform and connected with said latch and wound around the drum whereby the slack of said flexible element is automatically taken up and said flexible element is maintained uniformly taut,

2. A tripping device for the latch of a dumping door of a bucket of apower shovel having the usual equipment including a re volving platform, a boom carried by the platform, a dipper stick mounted on the boom and crowding mechanism for the dipper stick and comprising manually operable means supported on the revolving platform within reach and control of the operator, at single flexible element directly engaged with and directly controlled by said manually operable means on said revolving platform and connected with said latch, and means cooperable with the flexible element to compensate for the movement of the dipper stick under the influence of its crowding mechanism whereby said flexible element is maintained uniformly taut in all positions of thedipper stick.

3. A trlpping device for the latch of a dumping door of a power shovel having the usual equipment including a revolving platform and a shipper shaft, and comprising a sheave supported on the revolving platform in proximity to the operators osition thereon, a controlling lever for the s eave also supported on the revolving platform within reach and convenient control of the operator, a drum connectible with the shipper shaft and a flexible element trained around the sheave and connected with the latch and wound around the drum whereby the slack of said flexible element is automatically taken up to maintain the flexible element uniformly taut.

4, A tripping device for the 'latch of a dumping door of a bucket of a power shovel having a shipper shaft and comprising a shaft pivotally supported on the shovel in proximity to the operators position, a handle fixed to said shaft for rotating the same, a sheave frame fixed to the shaft and oscillated thereby, a sheave mounted in said sheave frame, a single cable having an intermediate portion extending around said sheave and having one end portion connected to said latch, and a drum adapted for attachment to the shipper shaft, the other end of saidcable being wound on said drum whereby the slack of the cable is automatically taken u .In witness whereof I l iereto aflix my signature.

HOLGER L. MITCHELL. 

